CoupeLeicht600

The CEL came on and read "Main Catalyst Below Threshold (Bank 2)." I'm fairly certain my catalytic converter is gone. It's a 2002 CL600 with over 108,000 miles on it, so I guess I got pretty good use out of the cat. I read some of the other posts on this topic, but I wanted to find out where to get the part. I found one link:

http://www.mercedesbenzgenuineparts....&siteid=214269

I'm trying to figure out which cat it is, cause the car has 4. Any help is appreciated. I have an independent mech who can do this, but I wanted to get the parts myself. The dealer will slaughter me with the job and I just got it back with 3 new oxygen sensors. Thanks everyone!

CoupeLeicht600

For some reason, the link is not working. If you type in "catalytic converter" for 2002 CL-Class, you'll be able to find it. Also, Arkansas doesn't have any emissions standards/laws, so it's not illegal to not have a cat.

hcetzneb

So are you looking to fix it or remove the cats... That code is for the main cat which is for the front cat. But if you what to just remove the cats just have the computer flashed so you dont get a light

CoupeLeicht600

Well, I'm still debating on whether or not to keep the cats. My original assumption was that if I didn't replace the cats, I would somehow get degraded combustion and/or mess up my oxygen sensors. I recently had 3 of the 4 oxygen sensors replaced and come to think of it, could they have failed due to the faulty cat?

I did speak with Fluid Motor Union (a high-performance tuner in Chicago) and they told me that I could get rid of the cats and tune it up for more performance.

But, at the moment, I'm looking to replace the bad cat. Let me know what you think?

lkchris

Lots of times a cat can't do it's job because the engine is sending it a mixture so off it can't cope. This due to bad MAF sensor.

It's pretty easy to get misled by codes, and it really is common for the MAF to be the problem. I'd have a pro look at it. By "pro" I mean a dealer, not an independent who just wants to sell parts.

hcetzneb

02 cl600 dont have maf sensor they use speed density

hcetzneb

Your kinda right getting this code it could mean other things like the 02 are on there way out( but probably would have a 02 code) and the only other thing that would affect 1 bank would be either a intake tract leak or some sort of ignition/ fuel problem on that side of the motor could be going lean or rich on one side of the engine over loading the cat... But with all these other problems other codes would be there like misfire codes or 02 codes.

What this code means in benz terms is a efficiency code all this means... each cat has a before and after o2 and the rear one reads millasecond of flow ( it calculates it by the reading) so if the millaseconds is low it thinks its cloogged ( over 1200mill sec) if its low it thinks its broken up with a hole..

Then it will throw a cat efficiency code... This is why when you hollow the front cats out the cel goes on and if you remove the rears it stays off

CoupeLeicht600

That's interesting that you guys mentioned these points. I was having a discussion with my mechanic and he was telling me that it basically is an issue of "efficiency." Like you said, the issue is the richness/leanness mixture.

However, I was a bit confused about the "speed density" part/meter. I thought my CL did have a mass air flow sensor? I remember getting a misfire code from it a long time back when I plugged in the OBD-II scanner, and I changed it out--it costed about $400ish. Anyway, after speaking with some other forum members, I got mixed opinions. Some say that I really don't need the cats and also my performance is better, which I don't mind at all. But, then again, the car's ecu is a bit sensitive than most cars and I don't want to risk any long-term damage if I don't slice, remove, or replace the cats. It already has over 108k miles and so far the cats have held up way better than the 80k "expected" mileage mark. Only complaint I have is that the stupid oxygen sensors gave me a headache in the last two months which ultimately caused me to change 3 of them.

Can't complain...this is the cost of ownership for these vehicles.

CoupeLeicht600

I was trying to figure out how I would get my ecu flashed in order for it to not read the cat error codes? I'm assuming that the dealership isn't going to flash it because it's not a legit thing to do?

Chris Mathews

Hello, I have an 2001 e430 also giving the cat-efficiency codes. Can you point me to a good resource to have the ecu re-flashed to not display the code?

Thanks a bunch.
CM